scholarly journals Dual-beam intracavity optical tweezers with all-optical independent axial and radial self-feedback control schemes

2021 ◽  
Author(s):  
Tengfang Kuang ◽  
Zijie Liu ◽  
WEI XIONG ◽  
Xiang Han ◽  
Guangzong Xiao ◽  
...  
Keyword(s):  
Feedback Control ◽  
Optical Tweezers ◽  
Dual Beam ◽  
Control Schemes ◽  
All Optical

scholarly journals Evaluation of Process Control Schemes for Sour Water Strippers in Petroleum Refining

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 363
Author(s):  
Chii-Dong Ho ◽  
Yih-Hang Chen ◽  
Chao-Min Chang ◽  
Hsuan Chang
Keyword(s):  
Feedback Control ◽  
Prediction Models ◽  
Feedforward Control ◽  
Absolute Error ◽  
Dynamic Responses ◽  
Control Schemes ◽  
Online Measurements ◽  
Measurement Delay ◽  
Water Feed ◽  
Sour Water

For the sour water strippers in petroleum refinery plants, three prediction models were developed first, including the estimators of sour water feed concentrations using convenient online measurements, the minimum reboiler duty and the corresponding internal temperature at a specific location (Tstage,29). Feedforward control schemes were developed based on these prediction models. Four categories of control schemes, including feedforward, feedback, feedback with external reset, and feedforward-feedback, were proposed and evaluated by the rigorous dynamic simulation model of the sour water stripper for their dynamic responses to the sour water feed stream disturbances. The comparison of control performance, in terms of the settling time, integrated absolute error (IAE) of the NH3 concentration of the stripped sour water and IAE of the specific reboiler duty, reveals that FFT (feedforward control of Tstage,29) and FBA-DT3 (feedback control with 3 min concentration measurement delay) are the best control schemes. The second-best control scheme is FBAT (cascade feedback control of concentration with temperature).

scholarly journals Feedback Control for Optical Tweezers Instruments: Position Clamping and Detection Laser Intensity Stabilization

2009 ◽  
Vol 96 (3) ◽  
pp. 290a
Author(s):  
Heikki Ojala ◽  
Anders Korsbäck ◽  
Anders E. Wallin ◽  
Edward Haeggström
Keyword(s):  
Feedback Control ◽  
Optical Tweezers ◽  
Laser Intensity ◽  
Intensity Stabilization

scholarly journals Ultrafast optically induced spin transfer in ferromagnetic alloys

2020 ◽  
Vol 6 (3) ◽  
pp. eaay8717 ◽  
Author(s):  
M. Hofherr ◽  
S. Häuser ◽  
J. K. Dewhurst ◽  
P. Tengdin ◽  
S. Sakshath ◽  
...  
Keyword(s):  
Density Functional ◽  
Spin Dynamics ◽  
Research Area ◽  
Spin Transfer ◽  
Optical Manipulation ◽  
Functional Theory ◽  
Control Schemes ◽  
All Optical ◽  
Spin Excitations ◽  
Experimental Findings

The vision of using light to manipulate electronic and spin excitations in materials on their fundamental time and length scales requires new approaches in experiment and theory to observe and understand these excitations. The ultimate speed limit for all-optical manipulation requires control schemes for which the electronic or magnetic subsystems of the materials are coherently manipulated on the time scale of the laser excitation pulse. In our work, we provide experimental evidence of such a direct, ultrafast, and coherent spin transfer between two magnetic subsystems of an alloy of Fe and Ni. Our experimental findings are fully supported by time-dependent density functional theory simulations and, hence, suggest the possibility of coherently controlling spin dynamics on subfemtosecond time scales, i.e., the birth of the research area of attomagnetism.

scholarly journals Synchronization Control of Time-Varying Complex Dynamic Network with Nonidentical Nodes and Coupling Time-Delay

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Youjian Zhang ◽  
Wenjun Yan ◽  
Qiang Yang
Keyword(s):  
Time Delay ◽  
Feedback Control ◽  
Complex Networks ◽  
Hybrid Control ◽  
Dynamic Network ◽  
Time Varying ◽  
Static Feedback ◽  
Control Schemes ◽  
Coupling Time ◽  
Nonidentical Nodes

This paper addresses the synchronization problem for a class of complex networks with time-varying topology as well as nonidentical nodes and coupling time-delay and presents two efficient control schemes to synchronize the network onto any given smooth goal dynamics. The time-varying network is supposed to be bounded within a certain range, which cannot be controlled. Through the adoption of hybrid control with linear static feedback control and adaptive feedback control, two control schemes are derived to guarantee such complex networks to reach the global synchronization. Finally, a set of numerical simulation experiments are carried out and the results demonstrate the effectiveness of the suggested control solutions.

Feedforward Control of Solar Thermal Power Plants

1997 ◽  
Vol 119 (1) ◽  
pp. 52-60 ◽  
Author(s):  
A. Meaburn ◽  
F. M. Hughes
Keyword(s):  
Feedback Control ◽  
Solar Collector ◽  
Power Plants ◽  
Feedforward Control ◽  
Thermal Power ◽  
Control Loop ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Control Schemes ◽  
Feedforward Controller

In recent years the problem of controlling the temperature of oil leaving an array of parabolic trough collectors has received much attention. The control schemes developed have in general utilized a feedback control loop combined with feedforward compensation. The majority of the published papers place the emphasis almost entirely on the design of the feedback control loop. Little or no attention has been paid to issues involved in the design of the feedforward controller. This paper seeks to redress this imbalance by concentrating upon the design and development of a feedforward controller for the ACUREX distributed solar collector field at the Plataforma Solar de Almeria. Different methods of combining feedback and feedforward will be assessed and experimental results will be presented in order to support any theoretical observations made.

scholarly journals Single molecular elasticity of spectrin as studies by dual-beam optical tweezers

1999 ◽  
Vol 39 (supplement) ◽  
pp. S94
Author(s):  
M. Tomishige ◽  
S. Manno ◽  
Y. Takakuwa ◽  
A. Kusumi
Keyword(s):  
Optical Tweezers ◽  
Dual Beam
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